Ministers "bullied" academics who wrote a report criticising plans for identity cards, the director of the London School of Economics (LSE) has alleged.

The LSE report sparked a row after it claimed the cost of ID cards could reach three times the government's estimate of £6bn over 10 years.

Home Secretary Charles Clarke said the study was "technically incompetent".

In a letter to the Times, LSE's Howard Davies said the government had adopted a "bullying" approach to his team.

It is unfortunate that, on an issue where the civil liberties concerns are so serious, the government should have chosen to adopt a bullying approach to critics

Howard DaviesLSE

Mr Clarke said the findings of the study, published earlier this week were "fabricated" and did discredit to the LSE's reputation.

In a Commons debate on the subject, he also accused one of the academics who helped to prepare the report of being "partisan" because he was already set against the cards.

The report was the result of six months' work, involved the contributions of more than 60 people and had been overseen by a dozen professors from LSE, Mr Davies said in his letter.

'Honest views'

Mr Clarke had branded the study as "mad" before he had even seen it, Mr Davies added.

"The report is not, of course, a corporate LSE document," he said.

"It does, however, represent the honest and considered views of a team of experts.

"It is unfortunate that, on an issue where the civil liberties concerns are so serious, the government should have chosen to adopt a bullying approach to critics whose prime motivation was to devise a scheme which might work at an acceptable cost."

'Details leaked'

The LSE report also claimed plans for ID cards were too risky and lacked the trust of the public.

And the government's proposed system was so complex it could itself become a target of terrorists, the academics warned.

Responding to the letter, a Home Office spokesman said Mr Clarke stood by his comments last week.

"Details of the LSE report have been leaked to the media over a period of two weeks," he said.

"The Home Office was repeatedly asked to comment on those details and it therefore seemed appropriate to ask for a copy.